In applications such as rooftop air conditioning and refrigeration, drives used on the condenser fans can be exposed to temperatures as low as −40° C. As the drives are usually operated every day of the year, such cold environments can present problems to the smooth operation of the drives which generally cannot operate with the ambient temperature this low.
In order to allow drives to operate in low temperatures, one option is to replace a number of components of the drive, for example those components that are most susceptible to malfunctioning in low temperatures. Another solution is to place the drive in an enclosure and provide a separate power supply for a thermostatically controlled strip heater to maintain the drive within a typical 0-50° C. range, or any other temperature range the drive may ideally operate in. For example, the drive could be installed in a cabinet along with cabinet heaters, or else a special drive designed to cope with low ambient temperatures may be used. Such solutions, however, come with additional expense, and add to the overall cost and size of the drive, and introduce more components that can fail.
It is desirable, therefore, to provide a drive that may operate in low temperatures without the need to resort to additional components or without the need to house the drive in a separate enclosure. The present invention seeks to provide such a drive, as well as a method of operating a drive that may address these and other problems encountered in the art.